Thermal air flow sensor

Description

Background of the Invention

[0001] The present invention relates to a sensor for measuring flow rate of fluid, and more particular, to a thermal air flow sensor.

[0002] As an air flow sensor provided in an intake manifold of an internal combustion engine in automobiles, etc. to measure an intake air quantity, a thermal air flow sensor has become the mainstream because of its ability of direct detection of a mass air quantity.

[0003] Recently, attention has been paid to air flow sensors manufactured by means of the semiconductor micromachining technology because of high speed responsibility and capability of detection of reverse flow making use of a high speed in responsibility.

[0004] However, it is known that thermal air flow sensors with the use of a semiconductor substrate are varied in flow output characteristics due to invasion of dirt substances, such as oil, dust, etc., and moisture onto a rear surface of a detecting element. JP-A-2003-270016 discloses a thermal air flow sensor, in which a hollow is provided in a plate-shaped substrate to form a diaphragm and a porous water proofing body is provided at an opening of the hollow.

[0005] With the conventional, thermal air flow sensor, when a detecting element comprising the plate-shaped substrate formed with the hollow and the diaphragm is bonded to a support, a clearance between the rear surface of the detecting element and a detecting element mounting surface of the support is liable to vary widely in dimension and it is difficult to control the clearance in dimension. When the clearance varies widely in dimension, air flowing into the hollow varies in quantity and direction, so that a curve is produced in a flow characteristic curve to cause a decrease in product yield.

[0006] In order to avoid the problem, it suffices to fully shield the hollow (diaphragm rear surface) from a passage chamber (a detection chamber in which a detecting part of the detecting element is arranged), through which air being a measuring object flows. That is, it suffices to put the hollow in a sealed state. Specifically, it suffices to bond whole periphery of the hollow by means of an adhesive in a manner to surround the hollow, thereby sealing the inside of the hollow. Since in general, detecting elements are rectangular-shaped, it suffices to bond all sides of a rectangular configuration.

[0007] When the whole periphery of the hollow is bonded by means of an adhesive to seal the inside of the hollow, however, there is caused a problem that complete sealing cannot be performed because variation in temperature and pressure causes air in the hollow (diaphragm rear surface) to expand in volume to result in breakage of the detecting element.

[0008] DE 42 19 454 A1 relates to a mass flow sensor showing a ventilation hole between an underside of a membrane and the intake pipe. Furthermore, a ventilation opening is shown on a side of the measurement chip so that a pressure balance may be achieved between the underside of the membrane and the inside of the intake pipe.

[0009] DE 197 43 409 A1 and DE 10 2007 034 919 A1 relate to further conventional mass air flow sensors having a membrane and a hollow space underneath the membrane. Said hollow space is covered by a further membrane (DE 10 2007 034 919 A1) or by the sensor element itself (DE 197 43 409 A1).

[0010] It is an object of the invention to provide a thermal air flow sensor, which is hard to be influenced by air flow being a measuring object and able to prevent breakage of a diaphragm due to variation in temperature and pressure. Brief Summary of the Invention

[0011] In order to attain the object, a thermal air flow sensor according to claim 1 is provided.

[0012] According to the invention, there is provided a thermal air flow sensor capable of avoiding breakage of a detecting element due to variation in temperature and pressure and realizing high-precision measurement of air flow.

Brief Description of the Drawings

[0013] 

Fig. 1 is a cross sectional view of a first embodiment of a thermal air flow sensor according to the invention.

Fig. 2 is a view illustrating a manner, in which a thermal air flow sensor is mounted.

Figs. 3A and 3B are views schematically illustrating a detecting element of a thermal air flow sensor, Fig. 3A being a plan view, and Fig. 3B being a cross sectional view taken along line IIIB - IIIB in Fig. 3A.

Figs. 4A to 4D are views illustrating application configurations of an adhesive on a detecting element, Fig. 4A being a view showing an upper surface of the detecting element, Fig. 4B being a view showing a rear surface of the detecting element, Fig. 4C being a cross sectional view taken along line IVC - IVC in Fig. 4A, and Fig. 4D being a cross sectional view taken along line IVD - IVD in Fig. 4B.

Fig. 5A is a plan view illustrating a ventilation hole of the first embodiment, and Fig. 5B is a cross sectional view taken along the line VB - VB in Fig. 5A.

Fig. 6 is a cross sectional view of a second embodiment of the thermal air flow sensor according to the invention.

Fig. 7 is a cross sectional view of a third embodiment of the thermal air flow sensor according to the invention.

Fig. 8 is a plan view illustrating an application configuration of an adhesive in the third embodiment.

Fig. 9 is a cross sectional view of a fourth embodiment of the thermal air flow sensor according to the invention.

Fig. 10A is a plan view illustrating an application configuration of an adhesive in the fourth embodiment, and Fig. 10B is a cross sectional view taken along line XB - XB in Fig. 10A.

Fig. 11 is a cross sectional view of a thermal air flow sensor not forming part of the invention.

Fig. 12 is a plan view of the air flow sensor of figure 11.

Fig. 13 is a cross sectional view of another thermal air flow sensor not forming part of the invention.

Detailed Description of the Invention

[0014] A thermal air flow sensor according to the invention will be described hereinafter. In addition, air is adopted as fluid being a measuring object in the following descriptions but other fluids can also be made a measuring object.

Embodiment 1

[0015] Figs. 1 to 5 schematically show a thermal air flow sensor according to the invention.

[0016] First, an environment, in which the thermal air flow sensor is mount will be described with reference to Fig. 2.

[0017] The thermal air flow sensor 1 is mounted to an intake duct 701 and air flowing in an intake duct interior 702 enters a passage from an upstream side opening 11 of the thermal air flow sensor 1, goes through the passage, and goes out of a downstream side opening 12.

[0018] Also, since an intake duct exterior 700 is completely isolated from the intake duct interior 702, the intake duct exterior 700 is put in a windless state even when air flows in the intake duct interior 702.

[0019] Subsequently, shape of a detecting element will be described with reference to Fig. 3.

[0020] In general, the detecting element 50 is rectangular-shape. A detecting part of the detecting element 50 comprises a thin film region called a diaphragm 55, and the diaphragm 55 is arranged in a passage chamber 300 (see Fig. 1), through which air being a measuring object flows. In this case, the passage chamber 300, in which the diaphragm 55 is arranged, constitutes a detection chamber.

[0021] In general, the diaphragm 55 is formed by means of etching in a direction from a rear surface of the detecting element 50 to provide a hollow 200 on the rear surface. The purpose of making the diaphragm 55 a thin film is based on an advantage that reduction in thermal capacity mainly makes it possible to achieve an increase in thermal responsibility and to accomplish reduction in power consumption.

First embodiment

[0022] Subsequently, a first embodiment of a thermal air flow sensor according to the invention will be described with reference to Fig. 1.

[0023] In the present embodiment, the detecting element 50 is mounted on a LTCC (Low Temperature Co-Fired Ceramic) laminated substrate 60 (referred hereinafter to as ceramic substrate). A dent called a cavity 61 is provided in the ceramic substrate 60 so as to enable receiving the detecting element 50.

[0024] The detecting element 50 and the ceramic substrate 60 are connected electrically to each other by an Au wire 80.

[0025] All four sides of the detecting element 50 are bonded in the cavity 61 by means of an adhesive 150 as shown in Figs. 4A and 4C. At this time, the use of the adhesive forms a clearance in the order of 1 µm ∼ 100 µm between the rear surface of the detecting element 50 and a bottom surface of the cavity 61.

[0026] In this case, in order to isolate the hollow 200 of the detecting element 50 from the passage chamber 300, an application pattern of the adhesive 150 can adopt a manner of application in gaps between sides of the cavity 61 and sides of the detecting element 50 as shown in Figs. 4A and 4C, or a manner of application on the rear surface of the detecting element 50 as shown in Figs. 4B and 4D.

[0027] The ceramic substrate 60 is bonded to a resin member 70. The passage chamber 300 and a circuit chamber 400, in which driving circuit parts (electronic parts such as resistor, capacitor, LSI chip, etc.) 401 are mounted, is completely isolated by a resin part. In the case where a gap is generated between the resin part and the ceramic substrate, a high fluidity material such as adhesive or the like is filled in the gap to enable sure isolation between the passage chamber 300 and the circuit chamber 400.

[0028] Thereby, the hollow 200 of the detecting element 50 is structured not to be directly communicated with the passage chamber 300.

[0029] A ventilation hole 600 being a communicating passage for communication between the hollow 200 and the circuit chamber 400 comprises a through hole 600a of the cavity 61 and a slit 600b of the resin member 70.

[0030] Figs. 5A and 5B show the configuration of the ventilation hole 600 as viewed from a surface thereof.

[0031] Also, the provision of a ventilation hole 650 being a communicating passage for communication between the circuit chamber 400 and the intake duct exterior 700 makes pressure in the circuit chamber 400 equal to the atmosphere and makes pressure in the hollow 200 equal to the atmosphere. Thereby, a differential pressure between the hollow 200 and an upper surface of the detecting element 50 is eliminated whereby it is possible to avoid breakage of the diaphragm 55 due to volume expansion.

[0032] Also, in the embodiment, the ventilation hole 650 for communication between the circuit chamber 400 and the intake duct exterior 700 is separately provided to thereby make the hollow 200 of the detecting element 50 equal in pressure to an outside air but an outlet of the ventilation hole 600 may be directly communicated with the intake duct exterior 700.

[0033] In the first embodiment, a LTCC substrate is adopted as a ceramic substrate, on which the detecting element 50 is mounted, but a LTCC substrate may be replaced by another ceramic substrate, a print board, or a metallic substrate.

Second embodiment

[0034] Fig. 6 schematically shows a second embodiment of a thermal air flow sensor according to the invention. The second embodiment is the same in fundamental constitution as that of the first embodiment. In the second embodiment, a ventilation hole 600 for communication between a hollow 200 and a circuit chamber 400 is formed in a ceramic substrate 60.

[0035] While the second embodiment adopts a LTCC substrate as a ceramic substrate, on which a detecting element 50 is mounted, in the same manner as in the first embodiment, another ceramic substrate, a print board, or a metallic substrate may be adopted.

[0036] By forming the ventilation hole 600 in a single constituent member, assembling of respective constituent members is increased in degree of freedom of positional tolerance and it is possible to eliminate possibility that the ventilation hole 600 is interrupted at a joint face due to dislocation.

Third embodiment

[0037] Fig. 7 schematically shows a third embodiment of a thermal air flow sensor according to the invention.

[0038] A difference from the first embodiment resides in that while the detecting element 50 is mounted fully in the passage chamber 300 in the first embodiment, a detecting element 50 is mounted to straddle a passage chamber 300 and a circuit chamber 400 in the third embodiment. The third embodiment is the same in fundamental constitution as that of the first embodiment.

[0039] As described above, since the detecting element 50 is mounted to straddle the passage chamber 300 and the circuit chamber 400, a wall 70a of a resin part 70 for separation of the passage chamber 300 and the circuit chamber 400 is provided in contact with an upper surface of the detecting element 50.

[0040] In this case, by optimizing an application configuration of an adhesive for fixation of the detecting element 50, a hollow 200 can be communicated to the circuit chamber 400 and an intake duct exterior 700 even when a ventilation hole 600 is not provided in a constituent member such as a ceramic substrate 60 and the resin member 70.

[0041] Fig. 8 shows an application configuration of an adhesive 150 in the third embodiment. As shown in Fig. 8, a range indicated by an arrow A and disposed above the wall 70a of the resin part 70 is a region of the passage chamber 300 and a range indicated by an arrow B and disposed below the wall 70a is a region of the circuit chamber 400.

[0042] The application configuration of the adhesive is a pattern, in which a rear surface is bonded or side surfaces of three sides in total, that is, an upper side 50c, an air flow upstream side 50b, an air flow downstream side 50d of the detecting element 50 are bonded.

[0043] The application configuration completely isolates the hollow 200 from the passage chamber 300.

[0044] However, it is necessary to adjust an application quantity of the adhesive 150 so that the wall 70a of the resin part 70 and the adhesive 150 bring about the isolated state.

[0045] Also, at the same time, a clearance 600c in the order of 1 µm - 100 µm is defined between the rear surface of the detecting element 50 and a bottom surface of a cavity in the same manner as in the first embodiment, whereby a ventilation hole 600 for communication between the hollow 200 and the circuit chamber 400 will be formed.

[0046] Also, in the third embodiment, a constituent part for separation of the passage chamber 300 and the circuit chamber 400 comprises the resin part 70 but a wall may be formed by an adhesive, gel, etc. Also, application configuration of an adhesive in this case may be the same as that in the third embodiment.

Fourth embodiment

[0047] Fig. 9 schematically shows a fourth embodiment of a thermal air flow sensor according to the invention.

[0048] The embodiment is the same in fundamental constitution as that of the third embodiment. A difference from the third embodiment resides in that all four sides 50a to 50d of a detecting element 50 are bonded and a slit 601 is provided to straddle a hollow 200 and the lower side 50d of the detecting element 50 as shown in Figs. 10A and 10B.

[0049] Since the provision of the slit 601 provides for communication between the hollow 200 and a circuit chamber 400, pressure in the hollow 200 balances with pressure on the outside to prevent breakage of a diaphragm 55.

[0050] The slit 601 can be formed by means of etching simultaneously when the hollow 200 is formed.

[0051] Fig. 11 schematically shows a thermal air flow sensor not forming part of the invention.

[0052] A difference from the first embodiment of the invention resides in that a detecting element 50 is bonded to a lead frame 450 and the lead frame 450 is packaged in a resin part 70.

[0053] The detecting element 50 is first bonded to the lead frame 450 and electrically connected to the lead frame 450 by an Au wire 80. Driving circuit electronic parts 401 are likewise mounted on the lead frame 450. Subsequently, the lead frame 450 is packaged in the resin part 70. At this time, since it is unnecessary to provide any circuit chamber 400, a ventilation hole 600 for opening of a hollow 200 of the detecting element 50 is formed in a manner to communicate the hollow 200 directly to an intake duct exterior 700.

[0054] Fig. 13 schematically shows another thermal air flow sensor not forming part of the invention.

[0055] A difference from the first embodiment of the invention resides in that an opening of a ventilation hole 600 of a hollow 200 is communicated indirectly with an intake duct interior 702.

[0056] The sensors has the same in fundamental constitution as that of the first embodiment. A manner, in which a detecting element 50 is bonded, is the same as that shown in Figs. 4A to 4D.

[0057] An outlet of the ventilation hole 600 of the hollow 200 of the detecting element 50 is opened not into a circuit chamber 400 but into a sub-passage chamber 350.

[0058] The sub-passage chamber 350 is an entirely different passage from a main passage chamber 300 for conduction of a duct air to the detecting element 50 and structured so that pressure is made the same.

[0059] Accordingly, the sub-passage chamber 350 is formed so that an air flowing in the sub-passage chamber 350 is made remarkably smaller in flow rate than an air flowing in the passage chamber 300.

[0060] Since the sub-passage chamber 350 is connected directly to the intake duct interior 702, the influence of an air going round to the hollow 200 is not zero but the effect of reduction in yield is produced in a conventional structure, in which a rear surface is not put in a sealed state, because an air entering into a hollow 200 is decreased in quantity.

Claims

1. A thermal air flow sensor having a hollow (200) in a portion of a detecting element (50) for detection of an air flow rate, wherein the detecting element is fixed to a sensor structural member (60, 70a, 70) so that the hollow (200) is not in direct fluid communication with a detection chamber (300) positioned on a reverse surface to the hollow (200),
characterized in that a communicating passage (600, 601) is provided to allow fluid communication between the hollow and a circuit chamber (400), in which a driving circuit (401) of the detecting element is mounted, wherein the communicating passage (600) allows pressure in the hollow (200) to balance with pressure in the circuit chamber (400), and said circuit chamber (400) has a ventilation hole (650) to make pressure in the circuit chamber (400) equal to the atmosphere.

2. The thermal air flow sensor according to claim 1, characterized in that said ventilation hole (650) is a first communicating passage for communication of the circuit chamber (400) and the exterior (700) of the intake duct (701).

3. The thermal air flow sensor according to claim 1, characterized in that the detecting element (50) is a rectangular-shaped element, and four sides of the rectangular-shaped element are bonded to the sensor structural member (60) to completely isolate the hollow (200) from the detection chamber (300).

4. The thermal air flow sensor according to claim 1, characterized in that the detecting element (50) is mounted on a Low Temperature Co-Fired Ceramic laminated substrate (60), or a print board, or a metallic substrate, a rear surface of the substrate (60) is wholly bonded to the sensor structural member (70), and the communicating passage (600) is formed by a combination of a through hole (600a) provided in a portion of the substrate and a slit (600b) provided in the sensor structural member (70).

5. The thermal air flow sensor according to claim 1, characterized in that the communicating passage (600) is formed in the substrate (60), on which the detecting element (50) is mounted.

6. The thermal air flow sensor according to claim 1, characterized in that the detecting element (50) is arranged to straddle the detection chamber (300) and the circuit chamber (400), the detecting element (50) is bonded to the substrate (60) to completely isolate the hollow (200) from the detection chamber (300), a space region, on which an adhesive is not applied, is existent on a portion of at least one of that side of the detecting element (50), which is positioned upstream of an air flow, that side, which is positioned downstream of the air flow, and that side, which is positioned in the circuit chamber, and the space region defines a portion of the communicating passage for communication between the hollow (200) and the circuit chamber (400).

7. The thermal air flow sensor according to claim 1, characterized in that the detecting element (50) in a rectangular-shape is arranged to straddle the detection chamber (300) and the circuit chamber (400), four sides (50a, 50b, 50c, 50d) of the rectangular-shaped detecting element (50) are bonded to the substrate (60) to completely isolate the hollow (200) from the detection chamber (300), and the detecting element (50) is formed with a slit (601), which is communicated to the hollow (200) and a side thereof positioned in the circuit chamber (400).

8. The thermal air flow sensor according to claim 1, characterized in that the detecting element (50) is electrically connected to a lead frame (450), which supports an electronic part and serves as electric wiring, the detecting element (50) and the lead frame (450) are packaged by a resin member (70), and the communicating passage (600) is formed in the resin member.

Ansprüche

1. Thermischer Luftdurchflusssensor, der einen Hohlraum (200) in einem Teil eines Detektionselements (50) zur Detektion einer Luftdurchflussmenge aufweist, wobei das Detektionselement an einem Sensorstrukturelement (60, 70a, 70) so befestigt ist, dass der Hohlraum (200) nicht in direkter Fluidkommunikation mit einer Detektionskammer (300), die auf einer rückwärtigen Oberfläche zu dem Hohlraum (200) angeordnet ist, steht,
dadurch gekennzeichnet, dass ein Verbindungskanal (600, 601) vorgesehen ist, um eine Fluidkommunikation zwischen dem Hohlraum und einer Schaltungskammer (400), in der eine Ansteuerschaltung (401) des Detektionselements montiert ist, zu ermöglichen, wobei der Verbindungskanal (600) ermöglicht, dass ein Druck in dem Hohlraum (200) sich mit einem Druck in der Schaltungskammer (400) ausgleicht und die Schaltungskammer (400) ein Lüftungsloch (650) aufweist, um den Druck in der Schaltungskammer (400) gleich dem Atmosphärendruck zu machen.

2. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Lüftungsloch (650) ein erster Verbindungskanal für eine Kommunikation der Schaltungskammer (400) und der Außenseite (700) des Einlasskanals (701) ist.

3. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Detektionselement (50) ein rechteckig geformtes Element ist und vier Seiten des rechteckig geformten Elements mit dem Sensorstrukturelement (60) gebondet sind, um den Hohlraum (200) von der Detektionskammer (300) vollständig zu isolieren.

4. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Detektionselement (50) auf ein mit Niedertemperatureinbrennkeramik laminiertes Substrat (60) oder eine Druckplatte oder ein metallisches Substrat montiert ist, eine hintere Oberfläche des Substrats (60) vollständig mit dem Sensorstrukturelement (70) gebondet ist und der Verbindungskanal (600) durch eine Kombination aus einem Durchgangsloch (600a), das in einem Teil des Substrats bereitgestellt ist, und einem Schlitz (600b), der in dem Sensorstrukturelement (70) bereitgestellt ist, ausgebildet ist.

5. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass der Verbindungskanal (600) in dem Substrat (60) ausgebildet ist, auf dem das Detektionselement (50) montiert ist.

6. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Detektionselement (50) dazu ausgelegt ist, die Detektionskammer (300) und die Schaltungskammer (400) zu überspannen, wobei das Detektionselement (50) mit dem Substrat (60) gebondet ist, um den Hohlraum (200) von der Detektionskammer (300) vollständig zu isolieren, ein Raumbereich, auf dem kein Haftmittel aufgebracht ist, auf einem Teil der Seite des Detektionselements (50), die stromaufwärts eines Luftstroms angeordnet ist, und/oder der Seite, die stromabwärts des Luftstroms angeordnet ist, und/oder der Seite, die in der Schaltungskammer angeordnet ist, vorhanden ist und der Raumbereich einen Teil des Verbindungskanals zur Kommunikation zwischen dem Hohlraum (200) und der Schaltungskammer (400) definiert.

7. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Detektionselement (50) in einer rechteckigen Form angeordnet ist, um die Detektionskammer (300) und die Schaltungskammer (400) zu überspannen, vier Seiten (50a, 50b, 50c, 50d) des rechteckig geformten Detektionselements (50) mit dem Substrat (60) gebondet sind, um den Hohlraum (200) von der Detektionskammer (300) vollständig zu isolieren, und das Detektionselement (50) mit einem Schlitz (601) ausgebildet ist, der mit dem Hohlraum (200) und einer Seite davon, die in der Schaltungskammer (400) angeordnet ist, kommuniziert.

8. Thermischer Luftdurchflusssensor nach Anspruch 1, dadurch gekennzeichnet, dass das Detektionselement (50) mit einem Leiterrahmen (450) elektrisch verbunden ist, der einen elektronischen Teil trägt und als elektrische Verdrahtung dient, das Detektionselement (50) und der Leiterrahmen (450) durch ein Harzelement (70) verpackt sind und der Verbindungskanal (600) in dem Harzelement ausgebildet ist.

Revendications

1. Capteur de débit d'air du type thermique ayant un creux (200) dans une portion d'un élément détecteur (50) pour la détection d'un débit d'air, dans lequel l'élément détecteur est fixé sur un élément structurel de capteur (60, 70a, 70) de sorte que le creux (200) n'est pas en communication fluidique directe avec une chambre de détection (300) positionnée sur une surface à l'envers du creux (200),
caractérisé en ce qu'un passage de communication (600, 601) est prévu pour permettre une communication fluidique entre le creux et une chambre à circuits (400) dans laquelle est monté un circuit pilote (401) de l'élément détecteur, dans lequel le passage de communication (600) permet à la pression dans le creux (200) de s'équilibrer avec la pression dans la chambre à circuits (400), et ladite chambre à circuits (400) comporte un trou de ventilation (650) pour rendre la pression dans la chambre à circuit (400) égale à la pression atmosphérique.

2. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que ledit trou de ventilation (650) est un premier passage de communication pour une communication de la chambre à circuits (400) et de l'extérieur (700) du conduit d'admission (701).

3. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que l'élément détecteur (50) est un élément de forme rectangulaire et quatre côtés de l'élément de forme rectangulaire sont collés à l'élément structurel de capteur (60) pour isoler complètement le creux (200) vis-à-vis de la chambre de détection (300).

4. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que l'élément détecteur (50) est monté sur un substrat stratifié en céramique cocuite à basse température (60), ou une carte à circuits imprimés, ou un substrat métallique, une surface postérieure du substrat (60) est entièrement collée à l'élément structurel de capteur (70), et le passage de communication (600) est formé par une combinaison d'un trou traversant (600a) prévu dans une portion du substrat et d'une fente (600b) prévue dans l'élément structurel de capteur (70).

5. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que le passage de communication (600) est formé dans le substrat (60) sur lequel l'élément détecteur (50) est monté.

6. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que l'élément détecteur (50) est agencé pour chevaucher la chambre de détection (300) et la chambre à circuits (400), l'élément détecteur (50) est collé sur le substrat (60) pour isoler complètement le creux (200) vis-à-vis de la chambre de détection (300), une région de l'espace, sur laquelle un adhésif n'est pas appliqué, existe sur une portion d'un côté au moins parmi le côté de l'élément détecteur (50) qui est positionné en amont d'un flux d'air, le côté qui est positionné en aval du flux d'air, et le côté qui est positionné dans la chambre à circuits, et la région de l'espace définit une portion du passage de communication pour une communication entre le creux (200) et la chambre à circuits (400).

7. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que l'élément détecteur (50) de forme rectangulaire est agencé pour chevaucher la chambre de détection (300) et la chambre à circuits (400), quatre côtés (50a, 50b, 50c, 50d) de l'élément de détection de forme rectangulaire (50) sont collés au substrat (60) pour isoler complètement le creux (200) vis-à-vis de la chambre de détection (300), et l'élément de détection (50) est formé avec une fente (601), qui communique avec le creux (200) et un côté de celui-ci positionné dans la chambre à circuits (400).

8. Capteur de débit d'air du type thermique selon la revendication 1, caractérisé en ce que l'élément détecteur (50) est connecté électriquement à un cadre de liaison (450) qui supporte une partie électronique et qui sert de câblage électrique, l'élément de détection (50) et le cadre de liaison (450) sont enrobés par un élément en résine (70) et le passage de communication (600) est formé dans l'élément en résine.

Drawing